Abstract:
Yield response of Virginia Bunch peanuts to calcium fertilization was investigated on Cockatoo Sands of the Ord River Irrigation Area. Shallow incorporation of 1000 kg/ha limestone (90% CaCO3) before planting produced maximum yields of sound mature kernels. Additional top-dressings of calcium as gypsum at flowering produced no significant effects on yield. The residual value of calcium fertilizer was investigated under a cropping regimen of a peanut crop every year. Yields at the highest total soil calcium level tested (440 ppm) produced only 86% of maximum yield obtained with additional gypsum applications at flowering, and 7.5% of kernels produced from these plots exhibited 'dark plumule̠ symptoms of calcium deficiency. Presence of some residual limestone in large granules, by reducing availability of calcium for uptake by pods, may have produced these effects. There were highly significant positive linear relationships between kernel calcium content and total soil calcium, and between kernel calcium content and germination percentage. Highly significant negative relationships between soil and kernel calcium contents and presence of 'dark plumule̠ symptoms were also established.